Overdose prevention campaigns by users’ organizations and government agencies have been implemented in WA in response to rising concerns about the increased rate of heroin-related drug overdose. These campaigns provide overdose prevention messages, details on how to manage an overdose, and include training in and information on basic first aid. The goal of this study was to determine whether the number of ambulance overdose calls had increased in response to the interventions implemented. WA data were examined on a monthly basis for the period January 1996 to December 2000. The number of heroin-related overdose fatalities per month was the dependent variable used in the analysis. Variables, such as ambulance call-outs, market factors, calls to the Alcohol and Drug Information Service (ADIS), and number of drug charges and purity of seizures, were examined over the period of the study to determine whether a significant relationship to the number of fatalities existed. Results show that the only significant variables were time, the number of ambulance call-outs, and the interventions. It is important to note that there has been a decrease in the number of these call-outs over time. The proportion of overdose-related call-outs relating specifically to opioid overdose has fallen. The number of ambulance call-outs has fallen over this period despite overdose prevention and management programs encouraging users to call an ambulance as part of their overdose management protocol. The re-emergence in the use of amphetamines may have impacted on the number of such calls. It does appear that there has been a reduction in the number of deaths in the latter months of this time-series. There has been a recent decrease in the number of heroin-related calls made to the ADIS line. Other factors are probably responsible for the decrease in heroin overdose deaths in the latter months, even though the interventions did reduce the number of such deaths shortly after their implementation. 3 figures, 1 table, 32 references